I've posted this on some other forums, but figured you guys on the Hide might like to see it. I present to you something truly special and exceptionally rare, an original OPL M73B2 rifle scope. This scope was manufactured in 1945 by the French firm Optique & Précision de Levallois (OPL) for the US Army. Even though it shares an "M73" moniker, this scope has nothing in common with the Weaver M73B1.
The B2 is a very robust scope that is noticeably heavier than its B1 counterpart. The B2 is unique in many aspects, the first of which are its annular elevation and windage adjustment rings. This style of adjustment ring is similar to the German Zf-41 and Swedish Aga m/42 scopes, however, the M73B2 relies on external adjustments (think Unertl). Unlike these European scopes, the the M73B2 doesn't move anything internally, the scope body moves in the mounting rings.
The scope does "click" in a similar manner as the B1 in regards to the elevation/windage adjustments. Just like the B1, the B2 utilizes a piece of notched spring steel that falls into a groove in the elevation/windage knob. You can't see it in the pictures, but on the B2 this piece of spring steel is on the bottom of the scope.
However, this design does have its shortcomings. When you adjust the elevation ring, the windage ring will move slightly out of place, and vice versa. I assume that this would shift the bullet's desired trajectory and subsequent impact.
The M73B2's elevation ring is also bullet drop compensated out to 1,000 yards or meters (not sure which). Want to shoot a target at 600 yards/meters? Just turn the ring to the number 6 (and watch your windage ring to make sure it didn't move with that adjustment!).
It's also nearly impossible to remove the scope mounting rings from the M73B2. After examining the front scope ring, it appears that a specialized spanner wrench is necessary for its removal. There is also a small glass window on the right hand side of this ring in order to let light into the scope (more on that in a paragraph below). The rear scope ring appears to be a housing of some sort, but there's no way in hell I'm taking it apart to find out how everything works and is held together!
As you can see from the pictures, the B2 uses a normal Redfield 1903A4 base. I've heard that an experimental base was developed, but I've never seen one and I have no idea what would be different about it.
If you look at the pictures of the M72B2 in Plaster's book or in the 2008 Stern estate auction, the bases' windage screws are quite different than the normal Redfield windage screws. The windage screws in those photos are pretty much over-sized thumbscrews. Maybe for quick detach purposes?
In regards to the bases' windage screws, they actually have to be cut down in order to properly hold the scope to the base. The bottom of the B2's rear scope ring is actually smaller in size than the bottom of a normal Redfield scope ring. This means that two regular screws will hit each other inside the base without securing the B2's rear scope ring. When these base windage screws are cut/shaved down, they don't hit each other and the screw heads are able to secure the scope ring.
Now for the most fascinating part of the scope, the "illuminated" reticle! As you can see in the pictures below, the reticle is the standard post type and it has some sort of range finder in the upper left quadrant. Now for the interesting part. If you shine a light into the glass window that is located on the right side of the front scope ring, the reticle turns from black to a mesmerizing silvery-white! I assume that this feature was added to take advantage of full moon nights, where the ambient light could penetrate the scope and illuminate the reticle. This would allow the reticle to stand out against a dark target in the dead of night. The pictures below show this transition, but they don't fully capture how brilliant the reticle appears when it is illuminated! I believe that this is the very first scope ever made with some kind of "illuminated" reticle, but I don't know that for a fact. If you know of any that are older than this scope, please let me know!
In the pictures below, I tried to show what the glass window in the front ring looks like when there is a light shining through the objective lens. If you look closely, you can see the inverted reticle; which looks like an upside down "T" (enhanced photo with the inverted reticle circled in red). The "T" shape comes from the vertical stadia line and the two horizontal stadia lines. It also appears that the reticle is etched on the lens.
In a side-by-side comparison with an B1, the B2 has a slightly different finish. It appears to be more black, whereas the B1 appears to be more blue. Definitely not as interesting as the whole illuminated reticle thing, but worth pointing out.
And finally, the pictures!
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The B2 is a very robust scope that is noticeably heavier than its B1 counterpart. The B2 is unique in many aspects, the first of which are its annular elevation and windage adjustment rings. This style of adjustment ring is similar to the German Zf-41 and Swedish Aga m/42 scopes, however, the M73B2 relies on external adjustments (think Unertl). Unlike these European scopes, the the M73B2 doesn't move anything internally, the scope body moves in the mounting rings.
The scope does "click" in a similar manner as the B1 in regards to the elevation/windage adjustments. Just like the B1, the B2 utilizes a piece of notched spring steel that falls into a groove in the elevation/windage knob. You can't see it in the pictures, but on the B2 this piece of spring steel is on the bottom of the scope.
However, this design does have its shortcomings. When you adjust the elevation ring, the windage ring will move slightly out of place, and vice versa. I assume that this would shift the bullet's desired trajectory and subsequent impact.
The M73B2's elevation ring is also bullet drop compensated out to 1,000 yards or meters (not sure which). Want to shoot a target at 600 yards/meters? Just turn the ring to the number 6 (and watch your windage ring to make sure it didn't move with that adjustment!).
It's also nearly impossible to remove the scope mounting rings from the M73B2. After examining the front scope ring, it appears that a specialized spanner wrench is necessary for its removal. There is also a small glass window on the right hand side of this ring in order to let light into the scope (more on that in a paragraph below). The rear scope ring appears to be a housing of some sort, but there's no way in hell I'm taking it apart to find out how everything works and is held together!
As you can see from the pictures, the B2 uses a normal Redfield 1903A4 base. I've heard that an experimental base was developed, but I've never seen one and I have no idea what would be different about it.
If you look at the pictures of the M72B2 in Plaster's book or in the 2008 Stern estate auction, the bases' windage screws are quite different than the normal Redfield windage screws. The windage screws in those photos are pretty much over-sized thumbscrews. Maybe for quick detach purposes?
In regards to the bases' windage screws, they actually have to be cut down in order to properly hold the scope to the base. The bottom of the B2's rear scope ring is actually smaller in size than the bottom of a normal Redfield scope ring. This means that two regular screws will hit each other inside the base without securing the B2's rear scope ring. When these base windage screws are cut/shaved down, they don't hit each other and the screw heads are able to secure the scope ring.
Now for the most fascinating part of the scope, the "illuminated" reticle! As you can see in the pictures below, the reticle is the standard post type and it has some sort of range finder in the upper left quadrant. Now for the interesting part. If you shine a light into the glass window that is located on the right side of the front scope ring, the reticle turns from black to a mesmerizing silvery-white! I assume that this feature was added to take advantage of full moon nights, where the ambient light could penetrate the scope and illuminate the reticle. This would allow the reticle to stand out against a dark target in the dead of night. The pictures below show this transition, but they don't fully capture how brilliant the reticle appears when it is illuminated! I believe that this is the very first scope ever made with some kind of "illuminated" reticle, but I don't know that for a fact. If you know of any that are older than this scope, please let me know!
In the pictures below, I tried to show what the glass window in the front ring looks like when there is a light shining through the objective lens. If you look closely, you can see the inverted reticle; which looks like an upside down "T" (enhanced photo with the inverted reticle circled in red). The "T" shape comes from the vertical stadia line and the two horizontal stadia lines. It also appears that the reticle is etched on the lens.
In a side-by-side comparison with an B1, the B2 has a slightly different finish. It appears to be more black, whereas the B1 appears to be more blue. Definitely not as interesting as the whole illuminated reticle thing, but worth pointing out.
And finally, the pictures!
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i346.photobucket.com\/albums\/p414\/nied0044\/ScopeM73B2_Dsc04739_final_zps9twc0a4e.jpg"}[/IMG2]
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